From 6aed475557032a7ff9009e9b4b691b40b561876a Mon Sep 17 00:00:00 2001
From: Angelo Compagnucci <angelo@amarulasolutions.com>
Date: Tue, 8 May 2018 16:08:44 +0200
Subject: [PATCH] build.go: explicit option for crosscompilation

Actually if GOHOSTOS == GOOS || GOHOSTARCH == GOARCH the go build system
assume it's not cross compiling and uses the same toolchain also for the
bootstrap.  This is a problem in case the cross compilation mandates a
different toolchain for bootstrap and target.  This patch adds
GO_ASSUME_CROSSCOMPILING varible to assure that in case of cross
compilation CC_FOR_TARGET can be different from CC.

Signed-off-by: Angelo Compagnucci <angelo@amarulasolutions.com>
Signed-off-by: Anisse Astier <anisse@astier.eu>
---
 src/cmd/dist/build.go | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/cmd/dist/build.go b/src/cmd/dist/build.go
index 7c44c4a605..03500920c4 100644
--- a/src/cmd/dist/build.go
+++ b/src/cmd/dist/build.go
@@ -286,12 +286,13 @@ func xinit() {
 // $CC_FOR_goos_goarch, if set, applies only to goos/goarch.
 func compilerEnv(envName, def string) map[string]string {
 	m := map[string]string{"": def}
+	crosscompiling := os.Getenv("GO_ASSUME_CROSSCOMPILING")
 
 	if env := os.Getenv(envName); env != "" {
 		m[""] = env
 	}
 	if env := os.Getenv(envName + "_FOR_TARGET"); env != "" {
-		if gohostos != goos || gohostarch != goarch {
+		if gohostos != goos || gohostarch != goarch || crosscompiling == "1" {
 			m[gohostos+"/"+gohostarch] = m[""]
 		}
 		m[""] = env
-- 
2.35.1

